Formation of methanethiol and dimethyl disulfide in crushed tissues of broccoli florets and their inhibition by freeze-thawing.

The formation of methanethiol and dimethyl disulfide in crushed, homogenized, and frozen-thawed tissues of broccoli florets was investigated. These volatile sulfur compounds were produced in crushed florets, but their formation was inhibited in frozen-thawed tissues. Only dimethyl disulfide was formed in homogenized tissues. High pH treatment triggered the release of dimethyl disulfide in frozen-thawed tissues and also enhanced the action of cysteine sulfoxide lyase in all disrupted tissues. Methyl methanethiosulfinate and methyl methanethiosulfonate were not detected in crushed florets; thus, the favored mechanism for the formation of methanethiol and dimethyl disulfide is the chemical disproportionation of methanesulfenic acid. In contrast, the formation of dimethyl disulfide in frozen-thawed and homogenized tissues occurs from the chemical disproportionation of methyl methanethiosulfinate that was detected in these tissues. The inhibition of dimethyl disulfide production during freeze-thawing must be caused by a sudden drop in the pH of the tissue, adherence of dimethyl disulfide on the tissue surfaces, and weakening of the cysteine sulfoxide lyase activity under acidic conditions.

Citation

Artemio Z Tulio, Hiroyuki Yamanaka, Yoshinori Ueda, Yoshihiro Imahori. Formation of methanethiol and dimethyl disulfide in crushed tissues of broccoli florets and their inhibition by freeze-thawing. Journal of agricultural and food chemistry. 2002 Mar 13;50(6):1502-7

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PMID: 11879028

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